Methods for Casting Airways
Joan Gil in Models of Lung Disease, 2020
Metallic alloys can be made with remarkably low melting points, but probably the most often used is Woods metal, which has a melting point of 70 °C. It has to be poured into a dry and fixed lung to avoid deformation by its weight and the problems that might result from a water/molten metal interface. It can pass all the way down to alveoli, where a heavy cast that is extremely difficult to prune can result. To prevent this, careful control of temperatures is required. In the past it has been used to make final negative casts, but the more modern materials are better suited to this purpose. It is still used to make the negative cast mold for positive casts, since it is strong and rigid but can be melted out of the positive.
Other Hazards in Clinical NMR Examinations
Bertil R. R. Persson, Freddy Ståhlberg in Health and Safety of Clinical NMR Examinations, 2019
A wide range of metallic prostheses is available. They are composed of either stainless steel or titanium- or cobalt-based alloys. There are also other implanted metallic devices such as hydrocephalus shunt systems (Holter Housner valve, Holter valve and reservoir, metal shunt connector, Hakein valve) and intrauterine devices (Copper 7 and Tantalum T). Pusey et al.18 evaluated various prostheses for tortional forces in different magnet systems operating at 0.3 to 1.5 T. They found that all orthopedic devices were weakly magnetic but with no or minimal tortional forces. For the hydrocephalus systems and intrauterine devices there were no significant tortional forces.
Basics of magnesium biodegradation
Yoshinobu Onuma, Patrick W.J.C. Serruys in Bioresorbable Scaffolds, 2017
The detailed metallurgical and metal physical reasons for the use of various components in magnesium alloys have been described in the literature [25,26]. An increasing amount of an alloying element added to the bulk material usually increases proportionally the specific physical or mechanical effect of this element [4,26]. There are many possibilities for alloy composition and processing, resulting in various microstructure-property relationships and in great differences in the strength, ductility, creep resistance, and resorption time of the alloy [4,21]. A wide range of mechanical properties can be obtained by varying the working environment the scaffold is made in [26].
The era of biofunctional biomaterials in orthopedics: what does the future hold?
Published in Expert Review of Medical Devices, 2018
Mubashar Rehman, Asadullah Madni, Thomas J. Webster
Metals and metal alloys were the first materials to be used as orthopedic devices in the form of plates, wires, rods, pins, needles, and screws. They were exclusively used for weight bearing parts of the body due to biocompatibility and desirable mechanical properties. Metal alloys are a mixture of metals wherein the basic properties of the metals are changed (Table 1). For orthopedics, commonly used stainless steel contains chromium (Cr, 17–20%), nickel (Ni, 12–14%), molybdenum (Mo, 2–3%), and carbon (C, 0.03%) [14]. Cr is added to stainless steel to make it resistant to corrosion caused by a diverse biological environment due to the spontaneous formation of a Cr2O3 layer. Ni gives an ‘austenitic’ structure which contributes strength and toughness. Mo also imparts corrosion resistance especially that which is caused by electrolytes such as chlorides. C is added for strength and hardness. Stainless steel also contains a minor amount of nitrogen, manganese, sulfur, phosphorus, and silicon. Ni-free stainless steel was prepared with high Cr content (20%) where manganese (Mn) and nitrogen (N, 0.3%) were used to make the austenitic structure.
Discrepancy in alloy composition of imported and non-imported porcelain-fused-to-metal (PFM) crowns produced by Norwegian dental laboratories
Published in Biomaterial Investigations in Dentistry, 2020
Håvard Jostein Haugen, Brandon Michael Soltvedt, Peter N. Nguyen, Hans Jacob Ronold, Gaute Floer Johnsen
Subsequently, the crowns were grouped according to laboratories, alloy-type and organized in predetermined categories defined as: No deviation included crowns with only minor deviations in major constituents (elements that comprised >20 wt. %) and slight deviations in additional elements that comprised <10 wt. %. Small deviation included crowns with deviations <5 wt. percentage concerning major constituents and/or deviations >1 wt. % in additional elements that comprised <10 wt. %. Large deviation included deviations >5wt. % concerning major constituents and missing additional elements. This category also included crowns with elements that should not be found in the relevant alloys such as aluminum (Al) or were not specified. Incorrect alloy refers to crowns that comprised of elements similar to a different type of alloy. For example, a crown marked as CopraBond K with results showing elements such as silver (Ag) and palladium (Pd) and is likely an Argelite61 alloy. Unspecified alloy were crowns delivered without or with lacking alloy information.
Estimates of environmental loading from copper alloy materials
Published in Biofouling, 2020
Patrick J. Earley, Brandon L. Swope, Marienne A. Colvin, Gunther Rosen, Pei-Fang Wang, Jessica Carilli, Ignacio Rivera-Duarte
The difference in pseudo steady-state release rate influences biofouling control. The traditional net had the lowest PSS release rates of <0.5 µg cm−2d−1, but it also had the most biofouling growth, based on visual assessment, during the deployment timeframe (Figure 6). In contrast, the PSS release rate for the four copper alloy materials, 1.4 to 6.9 µg cm−2d−1, was able to prevent biofouling growth on those materials for longer periods (Figure 6). Among the copper alloy materials, the Bronze and Net had multiple layers of material. These samples also appeared to have the highest degree of biofouling, which may be an artifact of the layering that created a three dimensional matrix, and may have increased the capability for fouling organisms to gain a foothold, despite the AF chemical properties of the materials also being increased with the multiple-layer approach.
Related Knowledge Centers
- Chemical Compound
- Copper
- Iron
- Opacity
- Mixture
- Atomic Ratio
- Gold
- Silver
- Carbon
- Silicon